Improvement in extensible braces for excavations



`W. T. DUNN & P. SILLIMAN.

Extensible Brace-for Excavations.

Nor. l68,085 Patented sep't. 28,1815.

'mllnflsg I hVE lmL 067% v Quang/5 Hsu/@MQW N. PETERS.FHOT0L|THDGHAPHER, WASHINGTON, D. C.

UNITED STATES PATENT GFEICE.

yWILLIAM T. DUNN, 0E PITTSBUEG, AND JAMES r. SILLIMAN, or ALLEGHENY,PENNSYLVANIA.

, VIMPROVEMENT IN EXTENSIBLE BRACES FOR EXCAVATIQNS.

Specification forming part of Letters Patent No. 168,085., datedSeptember 28, 1875; application led l September I, 1875.

To all whom it may concern Be it known that we, WILLIAM T. DUNN,

v and exact description thereof, reference being had to the accompanyingdrawing making a part of this specification, in Which-like lettersindicating like parts` Figure l illustrates our improvement as employedin actual use; and Fig. 2 is an enlarged view, partly in section, of thedevice itself.

In making deep cuts or excavations, especially in laying gas and Waterpipe,and in constructing sewers, difficulty is met with and dangerencountered in many soils from the caving in ot' the sidesor walls ofthe ex-v cavation. To avoid this heavy planks have been set up againstthe walls, directly opposite each other, anda cross-timber insertedbetween the two, which, it' not cut to the right length, had to be.driven down or recut, or wedged up at one or both ends, and timber outto the right length tor one part of the excavation is seldom of just theright length for another part. In any case material is Wasted, time andlabor lost, and the work, which often requires haste, is seriouslydelayed. -By our improvement We make an extensible brace or cross-piece,which is adjustable for all ordinary breadths of such excavations, andwhich is fitted with-a self-adjusting shoe at each end,

4whereby a broad, firm bearing is secured, and one not4 liable torotate'. At B B We have shown the Walls of an ordinarystreet-excavation. To prevent caving We set up the usual planks b b.Ourextensible brace or crosssupport consists of a tubular piece, a, 'anda threaded stem, a', 4which enters the tubular aperture of thepiece a,and is adjustable in or out, so as to increase or lessen the length ofthe entire device, by means of a screw-nut, c,

which works on the stem a', and in so doing bears against the end of thepiece a. To each end of the device We attach a shoe, e, which gives aseat, as at e', for the end of the piece to which it is attached, and byhaving a broad bearing on the plank b prevents the ends of theextensible parts from breaking through the'planks. The nut c is turnedby a Wrench or by arms c, or in any other suitable Way, and to preventthe parts a a', either or both, from rotating, we connect each shoe ewith its piece by means of a U, d, fixed to each shoe,

and passing through a hole or slot, s, as

shown. The joint permits the shoes e to adapt themselves to the shapeofthe plank b on which they bear, While at the same time accomplishingthe useful results above referred to.

The construction may be varied somewhat without any substantialdeparture from the thing invented, the essential elements being a bracemade in at least two pieces, extensible in or on each other by means of'a screwjoint, and a self-adjusting shoe aflixed at each outer end insuch manner as to prevent one or both the partsfrom rotating when thescrew is operated, and also so as to give a irm, even bearing againstthe sloping Walls of the excavation.

We claim herein as our invention- 1. The seltadjusting shoes e, capableof automatic adjustment to the slope of the excavation, permanentlyconnectedV with, to, and in combination With,the parts a a', extensibleby a screw-joint, substantially as set forth.

2. The shoes e attached to the outer ends of the extensible part-s a a,by means of U-shaped clips d playing looseiy in slots or holes s, thecombination of said parts named being substantially as set forth.

In testimony whereof We have hereunto set our hands.

WILLIAM T. DUNN. JAMES P.SILLIMAN. Witnesses:

JAMES M. CHRISTY, GEO. H. CHRISTY.

